Maintaining good oral hygiene is important for oral health and even overall well-being. Proper and regular tooth brushing is a basic and important part of an oral care regimen. Various toothbrushes, including electric toothbrushes, have been developed to facilitate effective tooth brushing. Researchers have continuously tried to improve the brushing quality, for example, by optimizing the brushing head, increasing the head rotation frequency, designing new cleaning techniques such as by way of ultrasound. Although some of these attempts have been successful in theory and even endorsed by dentists, high brushing quality has not been achieved in practice by many consumers. There are several explanations proposed. For example, at least one study reports that an adult brushes on average for 46 seconds while the recommended brushing time is generally accepted as 2 minutes. Studies even show that during this short brushing time consumers tend to brush unevenly, neglecting certain teeth surfaces and over-brushing others. This possibly leads to cavity formation and/or plaque accumulation in those surfaces where there is not enough brushing, and receding gums where there is too much brushing. Therefore, it is important for the consumer to receive real-time feedback on the brushing position (and time), to optimize their brushing procedure. Such feedback relies on the ability to precisely and accurately detect the position of the toothbrush in the mouth.
There have been efforts in developing position detection technology for about a decade. For example, U.S. Pat. No. 8,393,037 discloses a three-axis acceleration sensor mounted to a body of an electric toothbrush to estimate which portion is being brushed. A load sensor, provided inside the body of the toothbrush, for detecting brush pressure (a load imposed on the brush) is also disclosed. Any type of sensor including a strain gauge sensor, a load cell sensor, and a pressure sensor apparently can be utilized as the load sensor.
US 2012/266397 A1 (2012 Oct. 25) discloses an electric toothbrush estimating a brushing area by measuring the impedance between two electrodes by means of an impedance measuring unit.
U.S. Pat. No. 8,544,131 discloses an oral hygiene implement having a pressure indicator. The implement has a force sensor and an output source. A pivot point may be disposed in the handle, which is apparently beneficial for toothbrushes where the neck or head are replaceable.
However, to date no one has broadly and cost effectively commercialized this technology. There continues to be a need of providing non-intrusive, precise and/or accurate position detection at a low cost. Position detection technology will help users improve their brushing procedure so as to mitigate the occurrence of plaque and caries, as well as gum recession.